The present invention concerns devices and methods for testing the nervous system of a person. With the nervous system is in this application meant both that which is included in the brain and that which is arranged in other parts of the body. Injuries in the nervous system of the body may result in that the response of a person to different stimuli is delayed or may even be absent. Certain injuries in the nervous system may be difficult to detect. The present invention concerns devices and methods for testing the nervous system of a person, wherein an indication of injuries in the nervous system may be obtained.
U.S. Pat. No. 4,315,502 describes a device for training relaxation. The device comprises members for delivering light and sound signals to a person who is being trained. Light and sound signals may be emitted simultaneously or alternating. Furthermore, the left and the right eye or ear, respectively, may be stimulated simultaneously or alternating. The document in question describes however mainly relaxation training and does not describe the testing of the nervous system of a person.
U.S. Pat. No. 4,166,452 describes an apparatus for testing the response of a person to stimuli. These stimuli may concern vision, hearing and tactile sense. The testing is primarily done by measuring the reaction time of the person who is being tested in response to different stimuli. The apparatus that is described in the document comprises relatively complicated circuit solutions.
DE-C-4 318 336 describes a method and a device for training the ability to distinguish visual, additive and tactile stimuli. The document describes a device with a pulse generator that delivers electrical impulses. Electrical impulses to two different stimulation members, for example one for the right and one for the left side, may be delivered with an adjustable time delay. By varying this time delay, a person may be trained in distinguishing impulses which are close to each other in time.
The purpose of the present invention is to achieve devices and methods for in an efficient and relatively simple manner testing the nervous system of a person.
The purpose of the invention is achieved by a device for testing the nervous system of a person, comprising:
at least a first and a second stimulation member for application on or at the person, which stimulation members are arranged to stimulate at least one sense organ of the person,
a pulse generator arranged to deliver stimulation pulses to at least said first and second stimulation members,
an adjustment member in the nature of a time interval adjuster for adjusting the time interval at least between a stimulation pulse of the first stimulation member and a proximate stimulation pulse of the second stimulation member, wherein said time interval adjuster is arranged such that said time interval is substantially continuously adjustable from a negative to a positive value and such that said time interval is adjustable to a time interval where the person experiences said stimulation pulses from the first and the second stimulation members as being simultaneous,
a supervising unit arranged to determine said time interval when adjustment with the time interval adjuster has been done to the time interval where the person experiences said stimulation pulses from the first and the second stimulation members as being simultaneous, and
an output generator, for presenting said determined time interval to a user of the device.
With the help of the device, one or more sense organs may be stimulated with the help of stimulation members which are arranged at different parts of the body of the test person. Said time interval may then be adjusted until the test person experiences that the stimulation pulses from the first and the second stimulation members occur simultaneously. The supervising unit determines however if there still is a time interval between the delivered stimulation pulses. This time interval is presented to a user of the device. If there is a certain time interval between the stimulation pulses, in spite of the fact that the test person experiences these pulses as simultaneous, this may indicate the presence of injuries in the nervous system of the test person.
According to an embodiment of the invention, the device is arranged such that the stimulation pulses are delivered at a certain frequency f to said first and second stimulation members, wherein this frequency f is the same for the first and the second stimulation member. Since the stimulation pulses are delivered with a certain frequency, the test person has the possibility to sense many different stimulation pulses. With the help of the time interval adjuster, the difference in time may be continuously adjusted until the test person experiences the pulses from the first and the second stimulation members as being simultaneous. According to another embodiment of the invention, the device is arranged such that said time interval with the help of the time interval adjuster is adjustable up to a maximum absolute value_Txe2x80x94max, wherein _Txe2x80x94max less than 1/f. This means that the time interval with the help of the time interval adjuster may not be adjusted so much that it is unclear which pulse of the first stimulation member that corresponds to another pulse of the second stimulation member. According to this embodiment, the risk of lack of clarity in the interpretation of the determined time interval is thus reduced.
According to another embodiment of the invention, said first and second stimulation members are arranged to stimulate different sense organs of the person. A comparison of the reaction of a test person on the stimulation of different sense organs may thus be performed. The sense organs which are used are primarily hearing, vision and tactile sense. Taste and smell should not be excluded, but since these senses do not occur so exactly at a certain moment in time, it is somewhat more difficult to make a comparison with these senses.
According to another embodiment of the invention, said first and second stimulation members are arranged to stimulate the same sense organ of the person. Thereby, for example the stimulation of vision may be carried out for the left and the right eye, or for different parts of the visual field of the same eye. A corresponding test is also possible for other sense organs, primarily for hearing and for the tactile sense.
According to a further embodiment of the invention, the device comprises a time interval evaluator arranged to evaluate whether said determined time interval falls within a, for said stimulation pulses of the first and the second stimulation members, predetermined interval. Such a predetermined interval may for example have been determined in advance and stored in a memory. This predetermined interval may for example constitute a normal difference in time interval at a stimulation of different parts of a body of a test person, which stimulation may be carried out for the same or for different sense organs. The device may thus be arranged to analyse whether the determined time interval is to be considered as normal or not.
The purpose of the invention is also achieved by a method for testing the nervous system of a person, comprising:
applying at least a first and a second stimulation member on or at the person who is to be tested, which stimulation members are arranged to stimulate at least one sense organ of the person,
delivering stimulation pulses to at least said first and second stimulation members with the help of a pulse generator,
adjusting the time interval at least between a stimulation pulse of the first stimulation member and a stimulation pulse of the second stimulation member with the help of a time interval adjuster until the person who is being tested experiences said stimulation pulses from the first and the second stimulation members as being simultaneous,
determining said time interval when adjustment with the time interval adjuster been done until said time interval where the person experiences said stimulation pulses from the first and the second stimulation members as being simultaneous.
This method may for example be carried out with the above-mentioned device. By means of this method, the advantages described above in connection with device are thus achieved.
According to a preferred embodiment of the method, the adjustment of the time interval is done by the person who is being tested. The test person may thus adjust said time interval until the person experiences the stimulations as being simultaneous.
According to another preferred embodiment of the method, the stimulation pulses are delivered with a certain frequency f to said first and second stimulation members, wherein this frequency f is the same for the first and the second stimulation members. Thereby, the advantage described above, in connection with the device, is achieved.
According to another embodiment of the method according to the invention, said first and second stimulation members stimulate different sense organs of the person. According to a further embodiment of the method, said first and second stimulation members stimulate the same sense organ of the person. The method according to the invention thus comprises the possibilities which have been described above in connection with the device.
According to a further preferred embodiment, the method comprises evaluating whether said determined time interval falls within a, for said stimulation pulses of the first and the second stimulation members, predetermined interval. This evaluation may thus be used to determine whether the determined time interval is normal or not. If the determined time interval is not normal, the evaluation may comprise the determination of the fact that an injury may be the case in the nervous system.
The purpose of the invention is also achieved by a device for testing the nervous system of a person, comprising:
at least a first and a second stimulation member for application on or at the person, which stimulation members are arranged to stimulate at least one sense organ of the person,
a pulse generator arranged to deliver stimulation pulses to at least said first and second stimulation members,
an adjustment member for adjusting the difference in strength at least between a stimulation pulse of the first stimulation member and a stimulation pulse of the second stimulation member, wherein said strength difference adjuster is arranged such that said difference in strength is essentially continuously adjustable from a negative to a positive value and such that said difference in strength is adjustable to a difference where the person experiences said stimulation pulses from the first and the second stimulation members as having the same strength,
a supervising unit arranged to determine said difference in strength when adjustment with the strength difference adjuster has been done to the difference in strength where the person experiences said stimulation pulses from the first and the second stimulation members as having the same strength,
an output generator for presenting said determined difference in strength to a user of the device.
According to this embodiment, the strength of the stimulation pulses are thus adjusted instead of the time interval. It should be noted that a device according to the invention may be arranged to allow adjustment both of the strength and of the time interval. When using such a device it may thus be chosen whether the time interval or the strength is to be analysed.
According to an embodiment of this device, said first and second stimulation members are arranged to stimulate the same sense organ of the person. Since it may be difficult to compare the strength when different sense organs are stimulated, it is according to this embodiment preferred that the same sense organ is stimulated. It should however not be excluded that a comparison of the strength may be done also when stimulating different sense organs.
According to another embodiment of the device according to the invention, the device comprises a strength difference evaluator arranged to evaluate whether said determined difference in strength falls within a, for said stimulation pulses of the first and the second stimulation members, predetermined interval. Such an interval may for example indicate that which constitutes a normal difference in the experienced strength.
The purpose of the invention is also achieved by a method for testing the nervous system of a person, comprising:
applying at least a first and a second stimulation member on or at the person who is to be tested, which stimulation members are arranged to stimulate at least one sense organ of the person,
delivering stimulation pulses to at least said first and second stimulation members with the help of a pulse generator,
adjusting the difference in strength at least between a stimulation pulse of the first stimulation member and a stimulation pulse of the second stimulation member with the help of a strength difference adjuster until the person who is being tested experiences said stimulation pulses from the first and the second stimulation members as having the same strength,
determining said difference in strength when adjustment with the adjustment means has been done to the difference in strength where the person experiences said stimulation pulses from the first and the second stimulation members as having the same strength.
According to this method of the invention, the advantages described above in connection with the device are achieved.
Further advantages of the present invention will be clear from the remaining dependent claims and from the following description.